The mainstay of treatment of AMS is rest, fluids, and mild
analgesics: acetaminophen (paracetamol), aspirin, or ibuprofen. These
medications will not cover up worsening symptoms. The natural
progression for AMS is to get better, and often simply resting at the
altitude at which you became ill is adequate treatment. Improvement
usually occurs in one or two days, but may take as long as three or four
days. Descent is also an option, and recovery will be quite rapid.

A frequent question is how to tell if a headache is due to altitude. See
Golden Rule I. Altitude headaches are usually nasty, persistent, and
frequently there are other symptoms of AMS; they tend to be frontal (but
may be anywhere), and may worsen with bending over. However, there are
other causes of headaches, and you can try a simple
diagnostic/therapeutic test. Dehydration is a common cause of headache
at altitude. Drink one liter of fluid, and take some acetaminophen or
one of the other analgesics listed above. If the headache resolves
quickly and totally (and you have no other symptoms of AMS) it is very
unlikely to have been due to AMS.

Acetazolamide (Diamox®)

Acetazolamide (Diamox®) is a medication that forces the kidneys to
excrete bicarbonate, the base form of carbon dioxide; this re-acidifies
the blood, balancing the effects of the hyperventilation that occurs at
altitude in an attempt to get oxygen. This re-acidification acts as a
respiratory stimulant, particularly at night, reducing or eliminating
the periodic breathing pattern common at altitude. Its net effect is to
accelerate acclimatization. Acetazolamide isn't a magic bullet, cure of
AMS is not immediate. It makes a process that might normally take about
24-48 hours speed up to about 12-24 hours.

Acetazolamide is a sulfonamide medication, and persons allergic to sulfa
medicines should not take it. Common side effects include numbness,
tingling, or vibrating sensations in hands, feet, and lips. Also, taste
alterations, and ringing in the ears. These go away when the medicine is
stopped. Since acetazolamide works by forcing a bicarbonate diuresis,
you will urinate more on this medication. Uncommon side effects include
nausea and headache. A few trekkers have had extreme visual blurring
after taking only one or two doses of acetazolamide; fortunately they
recovered their normal vision in several days once the medicine was
discontinued.

Acetazolamide Use & Dosage:

For treatment of AMS: We recommend a dosage of 250 mg every 12 hours.
The medicine can be discontinued once symptoms resolve. Children may
take 2.5 mg/kg body weight every 12 hours.

For Periodic Breathing: 125 mg about an hour before bedtime. The
medicine should be continued until you are below the altitude where
symptoms became bothersome.

There is a lot of mythology about acetazolamide:

MYTH: acetazolamide hides symptoms

Acetazolamide accelerates acclimatization. As acclimatization occurs,
symptoms resolve, directly reflecting improving health. Acetazolamide
does not cover up anything - if you are still sick, you will still have
symptoms. If you feel well, you are well.

MYTH: acetazolamide will prevent AMS from worsening during ascent

Acetazolamide DOES NOT PROTECT AGAINST WORSENING AMS WITH CONTINUED
ASCENT. It does not change Golden Rule II. Plenty of people have
developed HAPE and HACE who believed this myth.

MYTH: acetazolamide will prevent AMS during rapid ascent

This is actually not a myth, but rather a misused partial truth.
Acetazolamide does lessen the risk of AMS, that's why we recommend it
for people on forced ascents. This protection is not absolute, however,
and it is foolish to believe that a rapid ascent on acetazolamide is
without serious risk. Even on acetazolamide, it is still possible to
ascend so rapidly that when illness strikes, it may be sudden, severe,
and possibly fatal.

MYTH: If acetazolamide is stopped, symptoms will worsen

There is no rebound effect. If acetazolamide is stopped, acclimatization
slows down to your own intrinsic rate. If AMS is still present, it will
take somewhat longer to resolve; if not - well, you don't need to
accelerate acclimatization if you ARE acclimatized. You won't become ill
simply by stopping acetazolamide.